When an edentulous patient is being considered for a full-arch implant-supported restoration, the conversation often centres on the number of implants and the choice of restorative material. But what happens several years after the prosthesis is delivered?
A new umbrella review has brought together long-term evidence on implant-supported complete-arch prostheses to examine not only how long these restorations survive, but also which complications tend to occur with different prosthetic designs and materials.
The review included systematic reviews reporting at least five years of follow-up for screw- or cement-retained implant-supported fixed complete-arch prostheses fabricated using metal-ceramic, metal-resin, veneered zirconia or monolithic zirconia.
Seven systematic reviews met the inclusion criteria.
Overall, the long-term survival figures were reassuring.
Prosthetic survival ranged from 89.5% to 96.8% over follow-up periods of five to 15 years. Implant survival was even higher, ranging from 95.2% to 99.2%.
In other words, the implants themselves continued to perform well over the long term, but technical complications involving the prosthesis remained an important part of maintenance.
The prosthesis may be where the problems begin
Among the complications reported across the included reviews, screw loosening occurred in approximately 5% to 15% of cases. Veneer chipping was reported in 15% to 35% of veneered zirconia restorations, while framework fractures were less common, occurring in fewer than 5% of cases.
The restorative material appeared to influence the type and frequency of complications.
Veneered zirconia demonstrated significantly higher rates of chipping compared with monolithic zirconia. This difference suggests that eliminating the veneering layer may reduce one potential source of technical failure.
Metal-ceramic frameworks, meanwhile, showed performance comparable with that of the other established restorative approaches in the analysis, with no significant difference reported in the comparison cited by the review.
The findings therefore point towards an important distinction: a high implant survival rate does not necessarily mean that the patient will remain completely free from prosthetic complications.
Four implants or six?
Another question frequently encountered in full-arch rehabilitation is whether increasing the number of implants from four to six provides better long-term survival.
According to the evidence synthesized in this umbrella review, implant number did not significantly influence implant or prosthesis survival when four and six implants were compared.
This does not mean that the number of implants is clinically irrelevant in every case. Rather, within the evidence evaluated by the review, increasing the number from four to six did not produce a statistically significant difference in long-term survival.
The review also examined biological complications. Peri-implantitis prevalence across the included evidence ranged from 4% to 18%, highlighting that long-term maintenance remains important even when implant survival is high.
The overall message from the review is reassuring: implant-supported complete-arch prostheses demonstrate high long-term implant and prosthetic survival, with implant survival consistently exceeding 95% beyond five years.
At the same time, the authors' conclusions should be interpreted within the limitations of an umbrella review. Only seven systematic reviews met the inclusion criteria, and those reviews incorporated different study designs, materials, prosthetic configurations and follow-up periods.
The evidence therefore supports informed material and design selection rather than a single universally superior full-arch solution.
Chairside Takeaway
Long-term implant-supported complete-arch prostheses show excellent survival, with implants surviving in more than 95% of cases across the reviewed evidence. But maintenance complications remain relevant. Material and design can influence the complication profile, with veneered zirconia showing more chipping than monolithic zirconia. The review also found no significant survival advantage for six implants compared with four.